Hard disk drives are common information storage devices. Referring to FIG. 1a, a conventional disk drive 100 essentially consists of a series of rotatable disks 101 mounted on a spindle, and a Head Stack Assembly (HSA) 130 which is rotatable about an actuator arm axis 102 for accessing data tracks on disks during seeking. The HSA 130 includes at least one arm 104 and HGA 150.
Referring to FIG. 1b, the HGA 150 includes a slider 103 (shown in FIG. 1c) having a reading/writing transducer (not shown) imbedded therein, and a suspension 190 to load or suspend the slider 103 thereon. When the disk drive is on, a spindle motor 102 will rotate the disk 101 at a high speed, and the slider 103 will fly above the disk 101 due to the air pressure drawn by the rotated disk 101. The slider 103 moves across the surface of the disk 101 in the radius direction under the control of the VCM. With a different track, the slider 103 can read data from or write data to the disk 101.
Concretely, the suspension 190 includes a load beam 106, a base plate 108, a hinge 107 and a flexure 105, all of which are assembled together.
The load beam 106 is connected to the base plate 108 by the hinge 107. A locating hole 112 is formed on the load beam 106 for aligning the load beam 106 with the flexure 105. And the load beam 106 is welded with the flexure for increasing the strength of the entire structure.
The base plate 108 is used to enhance structure stiffness of the whole HGA 150. A mounting hole 113 is formed on one end of the base plate 108 for mounting the whole HGA 150 to the motor arm 104 (referring to FIG. 1a). Another hole 110 is formed on the other end of the base plate 108, through which the base plate 108 connects with the flexure 105.
The flexure 105 is made of flexible material and runs from the hinge 107 to the load beam 106. The flexure 105 has a proximal end 119 adjacent the hinge 107 and a distal end 118 adjacent the load beam 106. A locating hole (not shown) is formed on the distal end 118 of the flexure 105 and aligned with the locating hole 112 of the load beam 106, thus obtaining a high assembly precision. A suspension tongue 116 is provided at the distal end 118 of the flexure 105 to carry the slider 103 thereon.
FIG. 1c shows a more detailed structure of the HGA 150 shown in FIG. 1b. As illustrated in the figure, a plurality of electrical traces 120 is formed on the flexure 105 along length direction thereof. One end of the electrical traces 120 is electrically connected to a preamplifier (not shown), and the other end thereof extends into the suspension tongue 116. The suspension tongue 116 has a plurality of bonding pads (not shown) formed thereon for coupling the slider 103. Concretely, the slider 103 is mounted on the suspension tongue 116, and the slider 103 has multiple bonding pads (not shown) formed thereon. The bonding pads of the slider 103 and the bonding pads of the suspension tongue 116 are electrically connected together by solder balls 135.
The following is a description of a conventional solder ball connection method for connecting the slider 103 to the suspension tongue 116.
FIG. 2 is a cross section view of the major portion of the HGA 150, and a partial cross sectional view of a conventional soldering device (not shown entirely). The load beam 106 is not illustrated here so as to simplify the description.
When carrying out a solder ball connection, the inclined HGA 150 is held by a holder (not shown) so that the connection surface 117a of the slider 103 and the connection surface 116a of the suspension tongue 116 face each other substantially perpendicular and each of those connection surfaces 117a and 116a is inclined substantially at 45° relative to a line 115.
The conventional soldering device (not shown) commonly includes a nozzle device 181, a solder ball feeding device (not shown), a laser unit (not shown) and a pressurized gas supplying unit (not shown). As shown in FIG. 2, the nozzle device 181 is tube shape which has a housing 182, an inner hollow passage 183 and a tip called nozzle 184. The solder ball feeding device stores many solder balls 135 and delivers one solder ball 135 to the nozzle 184 from the upper opening of the housing 182 through its passage 183 after the nozzle 184 is disposed at a predetermined position. At this time, the pressurized gas supplying unit supplies a nitrogen gas (N2) so as to prompt the solder ball 135 to move to the nozzle 184 with the action of the gravity.
In this state, the laser unit applies a laser beam to the solder ball 135 through the inner hollow passage 183 of the nozzle device 181 so as to make the solder ball 135 reflow. The solder ball 135 is then melted in this reflowing, getting both connection surfaces 117a and 116a of the slider 103 and the suspension tongue 116 wet and connected together. The nitrogen gas supplied at this time presses the melted solder against each connection surfaces 117a, 116a and covers the solder so as to be prevented from oxidation.
With the development of the compact and small-size slider, the bonding process between the slider and the suspension becomes more and more difficult. When the solder ball is supplied between the bonding pad of the slider and the bonding pad of the suspension by the solder ball feeding device, the accurate motion and location is difficult, which weakens the connection precision. In addition, as described above, the conventional connection method needs to provide the extra solder balls by the solder ball feeding device, thus the manufacturing cost and the apparatus cost are quite high, which is undesired to the manufacturer.
Thus, there is a need for an improved suspension, HGA and disk drive unit, a corresponding manufacturing method of a suspension and a method of connecting a suspension and a slider that do not suffer from the above-mentioned drawbacks.